(a) Technical Field
The present disclosure relates to a method of detecting wiring mismatch of a resolver. More particularly, it relates to a method of detecting wiring mismatch of a resolver for a Hybrid Electric Vehicle (HEV) to accurately analyze a fault code of the resolver, which detects the speed of a HEV traction motor and the angular position of a rotor.
(b) Background Art
Recently, due to high oil prices and carbon dioxide regulations, the development of eco-friendly vehicles, such as hybrid electric vehicles (HEVs), electric vehicles (EVs), and fuel cell vehicles (FCVs), for replacing typical internal combustion engine vehicles, has rapidly increased. These eco-friendly vehicles typically use an electric motor as a traction source, and as the traction motor, a Permanent Magnet Synchronous Motor (PMSM) having high power and efficiency (e.g., an Interior Permanent Magnet Synchronous Motor (IPMSM)) is widely used. Also, eco-friendly vehicles often include an inverter system for motor control, and a resolver to detect the absolute angular position θ of a rotor for motor control.
Generally, the resolver includes a stator, a rotor, and a rotary transformer. The coils of the stator and the rotor are wound such that flux distribution forms sine waves with respect to angular position. If a rotary shaft rotates after first and second input signals Rez+ and Rez− are applied to the primary side coils (i.e., input terminal), a magnetic coupling coefficient changes so that signals with changed amplitudes of carriers are generated from the secondary side coils (i.e., output terminals), whereby the secondary side coils are wound such that the signals change to form sine and cosine waves with respect to the angular position of the rotary shaft. As a result, the signals (i.e., output signals) generated from the secondary side coils have the forms of sine and cosine signals.
The resolver plays an important role in controlling a vehicle electric motor. Wiring mismatch of the resolver makes accurately measuring the position of the electric motor upon driving of the electric motor difficult, and accordingly, disables offset correction of the electric motor, thereby deteriorating the driving environment of the vehicle. In this regard, a conventional method of determining wiring mismatch of a resolver includes, for example: detecting a wiring mismatch of a resolver using deviation between plus (+) and minus (−) terminal signals that are first and second input signals Rez+ and Rez− of the primary side, and outputting signals of the secondary side, which are generated when the first and second input signals Rez+ and Rez− are applied. The test results are shown in FIG. 1. However, the conventional method of determining wiring mismatch of a resolver showed low accuracy in detecting a wiring mismatch, since the same infocode appeared with respect to different mismatching wirings. As shown in FIG. 1, when a first input signal Rez+ is shorted to a third output signal S3, a value of 13 that is an infocode appeared together with a value of 9. Accordingly, the conventional techniques fail to represent an accurate infocode.
Korean Patent Laid-open Application No. 10-2013-0029195 (hereinafter, simply referred to as Document 1) discloses a system for detecting a fault of a resolver. Document 1 suggests a method of determining a fault sensing signal using sine and cosine signals. However, Document 1 also has the problem that the same infocode appears with respect to different mismatching wirings. Therefore, a more effective method of improving diagnosis reliability is needed.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure, and therefore, it may contain information that does not form the related art that is already known in this country to a person of ordinary skill in the art.